This invention generally relates to mass transit vehicles. More particularly, this invention relates to a unique frame arrangement for a low floor mass transit vehicle.
Mass transit vehicles or buses are well known. There are a variety of configurations of such vehicles. Recently, the so-called low floor buses have become more desirable because of the easier access such vehicles provide to a variety of passengers. Because such buses have a lower profile, exiting or entering the bus is easier.
One approach to designing such buses is to essentially convert traditional bus style components into low floor bus components. Such a transition is not always successful, however, and tends to eliminate at least some of the advantages associated with a low floor bus design. Those skilled in the art are always striving to make improvements. For example, it is desirable to provide a lighter weight vehicle so that increased passenger capacity is available without exceeding legal weight limits. Additionally, more economical manufacturing techniques are desirable to increase the profitability for manufacturers of such vehicles.
This invention provides a unique mass transit vehicle frame that greatly simplifies the manufacturing process, presents substantial weight and cost savings and maximizes the benefits obtained by utilizing a low floor bus configuration.
In general terms, this invention is a frame for a mass transit vehicle. The inventive frame includes a stiff floor panel extending between a front and rear of the frame. A stiff roof panel is positioned above the floor panel. A plurality of pillars extend between the floor panel and the roof panel. The pillars are connected to the panels near ends of the pillars and near edges of the panels. A plurality of side panels are secured at least to the pillars such that the side panels carry shear stresses on the frame.
In one example, the roof and floor panels include a sandwich like construction having a first sheet and a second sheet with a reinforcing portion between the sheets and secured to them. The roof and floor panels in the preferred embodiment are stiff and strong in two directions. A first direction is lateral direction that extends generally across the frame from one side of the vehicle to the other. The second direction is a longitudinal direction from the front to the back of the vehicle.
Connecting brackets preferably are used to secure the pillars to the roof and floor panels. The connecting brackets in one example have a generally L-shaped configuration with a first support portion that is secured to the pillars and a second support portion secured to the corresponding panel. In one particular example where the roof and floor panels include two sheets, at least one of the bracket support portions is inserted between the two sheets of the panel and secured to a selected one of the sheets.
One example of the inventive arrangement also includes cantilevered seats mounted to the frame. In one example, the seats include front and rear cantilevered support members that are secured to corresponding ones of the pillars using mounting brackets. The mounting brackets have a butterfly-like configuration with a central portion secured to the seat and extending wing portions secured to a corresponding one of the pillars near ends of the wing portions.
One example embodiment of this invention includes a completely stainless steel frame. The various components of the frame in such an example are designed to accommodate spot welding most of the connections between the components.